1. Field of the Invention
The present invention relates to an internal diameter measurement device for measuring the internal diameter of a cavity. Priority is claimed on Japanese Patent Application No. 2008-6282, filed Jan. 15, 2008, the content of which is incorporated herein by reference.
2. Description of Related Art
Conventionally, an internal diameter measurement device is known which is inserted into a channel of various types of endoscopes for medical or industrial use, and then inserted into luminal organs such as the bronchial tubes or the esophagus, into gas piping or water piping, or into piping for machinery or equipment to thereby measure an internal diameter thereof (For example, refer to Patent Document 1: Japanese Examined Utility Model Application, Second Publication No. H2-44722).
Furthermore, an internal diameter measurement device is known which has a length measuring portion which expands and contracts in the radial direction and which can be coordinated with the action of an operating portion (For example, refer to Patent Document 2: Japanese Unexamined Patent Application, First Publication No. 2000-292108).
The internal diameter measurement device disclosed in Patent Document 1 is provided with a scale, both ends of which are connected by a wire, and which is provided at a distal end of an outer covering pipe such as a coil sheath. Dimensional measurements are performed using the scale.